MEIOFAUNA MARINA Biodiversity, morphology and ecology of small benthic organisms 14 pfeil MEIOFAUNA MARINA Biodiversity, morphology and ecology of small benthic organisms Volume 14 • July 2005 pages 1-207, 97 figs., 47 tabs. Editor-in-Chief Thomas Bartolomaeus, Freie Universität Berlin, Systematik und Evolution der Tiere, Königin-Luise-Str. 1-3, 14195 Berlin, Germany, Tel. + 49 - 30 - 83 85 62 88 / Fax + 49 - 30 - 83 85 39 16 Managing Editor Andreas Schmidt-Rhaesa, Zoomorphologie und Systematik, Morgenbreede 45, 33615 Bielefeld, Germany Tel. + 49 - 521 - 106 - 27 20 / Fax + 49 - 521 - 106 - 64 26, E-mail a.schmidt-rhaesa@uni-bielefeld.de Guest Editor M. Antonio Todaro, Dipartimento di Biologia Animale, Università di Modena e Reggio Emilia, Via Campi 213/d, 41100 Modena, Italia E-mail todaro.antonio@unimore.it Thomas Bartolomaeus Andreas Schmidt-Rhaesa Pedro Martinez Arbizu Werner Armonies Susan Bell Nicole Dubilier Peter Funch Marco Curini Galletti Gerhard Haszprunar Rony Huys Ulf Jondelius Reinhardt Møbjerg Kristensen Marianne K. Litvaitis Ken-Ichi Tajika Seth Tyler Magda Vincx Wilfried Westheide Editorial board Freie Universität Berlin, Germany Universität Bielefeld, Germany Deutsches Zentrum für Marine Biodiversitätsforschung, Wilhelmshafen, Germany Alfred-Wegener-Institut für Polar- und Meeresforschung, Wattenmeerstation List auf Sylt University of South Florida, Tampa, FL, USA Max-Planck-Institut für Molekulare Mikrobiologie, Bremen, Germany University of Åarhus, Denmark University of Sassari, Italy Zoologische Staatssammlung, München, Germany Natural History Museum, London, England University of Uppsala, Sweden Zoological Museum, University of Copenhagen, Denmark University of New Hampshire, Durham, NH, USA Nihon University School of Medicine, Tokyo, Japan University of Maine, Orono, ME, USA University Gent, Belgium Universität Osnabrück, Germany Meiofauna marina is published annually Subscriptions should be addressed to the Publisher: Verlag Dr. Friedrich Pfeil, Wolfratshauser Str. 27, D–81379 München, Germany PERSONAL SUBSCRIPTION: 48.– Euro INSTITUTIONAL SUBSCRIPTION: 96.– Euro Fees for mailing will be added Manuscripts should be addressed to the editors Bibliografische Information Der Deutschen Bibliothek Die Deutsche Bibliothek verzeichnet diese Publikation in der Deutschen Nationalbibliografie; detaillierte bibliografische Daten sind im Internet über http://dnb.ddb.de abrufbar. Copyright © 2005 by Verlag Dr. Friedrich Pfeil, München, Germany All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted in any form or by any means, electronic, mechanical, photocopying or otherwise, without the prior permission of the copyright owner. Applications for such permission, with a statement of the purpose and extent of the reproduction, should be addressed to the Publisher, Verlag Dr. Friedrich Pfeil, Wolfratshauser Str. 27, 81379 München, Germany. Printed by Athesia Druck GmbH, Bozen ISSN 1611-7557 Printed in Italy Verlag Dr. Friedrich Pfeil, Wolfratshauser Str. 27, D–81379 München, Germany Tel. + 49 - 89 - 74 28 27 0 • Fax + 49 - 89 - 72 42 77 2 • E-mail: info@pfeil-verlag.de • www.pfeil-verlag.de MEIOFAUNA MARINA Biodiversity, morphology and ecology of small benthic organisms 14 Verlag Dr. Friedrich Pfeil München ISSN 1611-7557 Volume 14 of Meiofauna Marina presents, with the only exception of the paper by Kapp & Giere, proceedings from the Twelfth International Meiofauna Conference (TWIMCO) held in Ravenna, Italy, from July 11-16, 2004. This conference was hosted by the International Association of Meiobenthologists (www.meiofauna.org) and organized by a committee from the universities of Modena and Reggio Emilia as well as Bologna. We are glad that Antonio Todaro (University of Modena and Reggio Emilia) acted as Guest Editor in this volume of Meiofauna Marina. Thomas Bartolomaeus, Chief Editor Andreas Schmidt-Rhaesa, Managing Editor Front cover photograph Nanaloricus mysticus was the first species of Loricifera to be described. Loricifera are now recognized as an abundant and typical element of diverse marine meiofaunal habitats. Photo kindly by Reinhardt Møbjerg Kristensen, Copenhagen, Denmark. Back cover photograph Light micrograph of the nerillid polychaete Nerillidium gracile from Roscoff, France. Dorsal view of live specimen (see Worsaae, this volume). 3 CONTENTS Tomassetti, Paolo, Oliver Voigt, Allen G. Collins, Salvatore Porrello, Vicki B. Pearse and Bernd Schierwater: Placozoans (Trichoplax adhaerens Schulze, 1883) in the Mediteranean Sea..................................................................................................................................... 5 Marotta, Roberto, Loretta Guidi, Lara Pierboni, Marco Ferraguti, M. Antonio Todaro and Maria Balsamo: Sperm ultrastructure of Macrodasys caudatus (Gastrotricha: Macrodasyida) and a sperm-based phylogenetic analysis of Gastrotricha ............................... 9 Hummon, William D., M. Antonio Todaro and Wayne A. Evans: Video Database for Described Species of Marine Gastrotricha ........................................................................... 23 Todaro, M. Antonio and Carlos E. F. Rocha: Further data on marine gastrotrichs from the State of São Paulo and the first records from the State of Rio de Janeiro (Brazil) .. 27 Guidi-Guilvard, Laurence D., Serge Dallot and Jean-Philippe Labat: Variations in space and time of nematode abundances at 2347 m depth in the North-Western Mediterranean ........................................................................................................................................ 33 Mouawad, Rita: Characterization of meiobenthic communities of Lebanese sandy beaches with emphasis on free-living marine nematodes ................................................ 41 Worsaae, Katrine: Systematics of Nerillidae (Polychaeta, Annelida) .................................... 49 George, Kai Horst and Pedro Martínez Arbizu: Discovery of Superornatiremidae Huys (Copepoda, Harpacticoida) outside anchialine caves, with the description of Gideonia noncavernicola gen. et sp. nov. from the Patagonian continental slope (Chile) .............. 75 Faraponova, Olga, Domenica De Pascale, Fulvio Onorati and Maria Grazia Finoia: Tigriopus fulvus (Copepoda, Harpacticoida) as a target species in biological assays ............. 91 Di Lorenzo, Tiziana, Donatella Cipriani, Paolo Bono, Ludovico Rossini, Paola De Laurentiis, Barbara Fiasca, Claudio Pantani and Diana M. P. Galassi: Dynamics of ground water copepod assemblages from Mazzoccolo karstic spring (central Italy) ................ 97 Maiolini, Bruno, Valeria Lencioni, Raffaella Berera and Vezio Cottarelli: Effects of flood pulse on the hyporheic harpacticoids (Crustacea, Copepoda) in two high altitude Alpine streams ......................................................................................................................... 105 Kapp, Helga and Olav Giere: Spadella interstitialis sp. nov., a meiobenthic chaetognath from Mediterranean calcareous sands ................................................................................. 109 Mohamed, Eiman, Said Al-Kady, Aisha Al-Kandari and Jamyla Al-Saffar: Meiofauna seasonal abundance in three Kuwaiti beaches .................................................................... 115 Calles, Alba, Magda Vincx, Pilar Cornejo and Jorge Calderon: Patterns of meiofauna (especially nematodes) in physical disturbed Ecuadorian sandy beaches ..................... 121 Moreno, Mariapaola, Valeria Granelli, Giancarlo Albertelli and Mauro Fabiano: Meiofaunal distribution in microtidal mixed beaches of the Ligurian Sea (NW Mediterranean) ....................................................................................................................................... 131 Mitwally, Hanan M. and Hassan B. Awad: Distribution of meiofauna in relation to abiotic and biotic factors in a semi-closed harbor in Alexandria, Egypt ............................. 139 Mitwally, Hanan M., Soha Shabaka, Hesham M. Mostafa and Youssef Halim: Distribution of meiofauna inside and outside a Cymodocea nodosa meadow in Alexandria, Egypt . 145 Burgess, Robert, Jyotsna Sharma, R. Scott Carr and Paul Montagna: Assessment of storm water outfalls in Corpus Christi Bay, Texas, USA using meiofauna .............................. 157 Gwyther, Janet: The effect of grazing gastropods on meiofaunal colonisation of pneumatophores in a temperate mangrove ................................................................................. 171 Meiofauna Marina, Vol. 14 4 Casu, Daniela, Giulia Ceccherelli, Alberto Castelli and Marco Curini Galletti: Impact of experimental trampling on meiofauna inhabiting rocky upper infralittoral bottoms at the Asinara Island Marine Protected Area (NW Mediterranean) ............................... 183 Skjaeggestad, Hanne and Patrick J. S. Boaden: Impact of intertidal oyster trestle-culture on the meiobenthos of a Strangford Lough sandflat ......................................................... 189 Westheide, Wilfried: Meiofauna geographic distribution: vicariance and dispersal .......... 201 Meiofauna Marina, Vol. 14 157 Meiofauna Marina, Vol. 14, pp. 157-169, 9 figs., 3 tabs., July 2005 © 2005 by Verlag Dr. Friedrich Pfeil, München, Germany – ISSN 1611-7557 Assessment of storm water outfalls in Corpus Christi Bay, Texas, USA using meiofauna Robert Burgess*, Jyotsna Sharma**, R. Scott Carr*** and Paul Montagna**** Abstract A previous Sediment Quality Triad (SQT) assessment was conducted at 36 sites in Corpus Christi Bay, Texas, U.S.A. to determine the degree of sediment quality and extent of contaminant impacts caused by storm water outfalls. The majority of sites were located near storm water outfalls, but other sites of concern (industrial and domestic outfalls, produced water discharges, and dredging activity), and reference sites were also evaluated. It was found that the macrofauna index of biotic integrity, sea urchin development and fertilization, and mysid growth and survival were significantly inversely correlated with sediment contaminants. The purpose of the current study was to determine if meiofaunal community characteristics (Harpacticoida species and Nematoda feeding groups) were also inversely correlated with contaminants. The four most contaminated storm water sites exhibited extreme reductions in measures of both macrofaunal and meiofaunal community integrity (indicated by reductions in nematode and harpacticoid abundance, and harpacticoid diversity). However, re-suspension was a confounding factor with organic pollutants at five relatively clean outfall sites, where it eliminated the harpacticoid copepod community, and negatively affected the macrofaunal community. The composition of nematode genera at all sites was consistent however the feeding groups composition was affected by sediment contaminants. Deposit feeding nematodes were abundant at all sites with the non-selective deposit feeders predominant. Predators and omnivores were the least abundant group. In general, of the 36 sites studied, the four most degraded sites (with lowest sediment quality) were storm water outfall sites. Keywords: Harpacticoida, Nematoda, Resuspension, Sediment Quality Triad, non-point sources Introduction Estuarine communities are increasingly susceptible to anthropogenic disturbances because of rapidly increasing coastal populations and subsequent shoreline development. The sources of anthropogenic contamination result from many human activities. Sources of contaminants can be categorized into two types, point and non-point, based on their origin. Most water * Texas Commission on Environmental Quality, Austin, Texas 78711, U.S.A. ** University of Texas-San Antonio, Department of Biology, San Antonio, Texas 78249, U.S.A. *** United States Geological Survey, Ecotoxicology Research Station, Texas A&M-Corpus Christi, Corpus Christi, TX 78412, U.S.A. **** University of Texas-Austin, Marine Science Institute, 750 Channel View Drive, Port Aransas, Texas 78373, U.S.A. Meiofauna Marina, Vol. 14 158 and sediment quality monitoring surveys have been focused on point sources, such as industrially produced waters, dredging, spills, and municipal wastewater discharges (Coull & Chandler 1992). Non-point sources, such as runoff from urban areas, agricultural runoff, landfill leakage, industrial runoff, and runoff from coastal construction projects have continued to increase, and have proved difficult to quantify. Non-point source contaminant loading can account for up to 80 % of the total pollutant load in estuaries surrounded by developed areas (Kennish 1998). In the United States, approximately 50 % of impaired estuarine shorelines are caused by urban runoff alone (Lindsey et al. 1997). Most urban runoff is drained by storm sewers into nearby bodies of water. This provides a point source discharge of non-point source pollutants. Corpus Christi (Texas, U.S.A.) storm water outfalls discharge directly into Corpus Christi Bay. Pollutants (e.g., metals or organic compounds) quickly flocculate and are deposited into sediments because the chemical complexes, which were soluble in mildly acidic rain water, become only sparingly soluble in the high pH and high salinity environment of the estuary (Libes 1992). The rapid change from fresh water to high salinities of Corpus Christi Bay causes flocculation of the pollutants near the outfalls, providing a concentrating mechanism. Consequently, acute biological responses would be likely near stormwater outfalls. One powerful technique to assess sediment quality is the Sediment Quality Triad (SQT) approach (Chapman 1990). The approach is to identify potential chemical dose with measures of bulk sediment contaminant concentrations; biological responses with toxicity measurements, and ecological responses with macrofaunal community indicators. Recently, Carr et al. (2000) used the SQT approach to assess sediment quality near outfalls in Corpus Christi Bay by measuring chemical indicators (sediment contaminant concentrations), biological indicators (toxicity responses by sea urchins, amphipods, and mysids), and ecological indicators (macrofauna community structure reduced to an index of biotic integrity). Overall, they sampled 36 sites and found four of the five most degraded sites (stations S1, S2, S9, S15, 2) were outfalls. Survivability was inversely correlated to contaminant concentrations and pollution sensitive macrofauna, but positively correlated with pollution tolerant macrofauna. There was no significant correlation between contaminants and macrofauna indicators. Meiofaunal samples were taken, but not analyzed. Also, the outfalls were along shorelines that are high energy environments, indicating that resuspension could be confounded with contaminants. Benthic communities integrate effects of all forms of disturbance, such as the cumulative effects of pollutants, as well as effects of physical disturbances. Therefore, assessment studies should include measurements of physical variables as well as pollutants (Hall 1994). Meiofauna have several attributes that make them good candidates for use in sediment quality assessments. 1) Meiofauna are sensitive to many types of anthropogenic perturbations (Coull & Chandler 1992; Giere 1993). 2) Most pollutants are highly concentrated in the sediments, therefore the benthos, both macrofauna and meiofauna, are continually exposed due by their association with sediments, and are more likely to exhibit effects due to the contamination (Reynoldson and Rodriguez 1999). 3) The meiofaunal community however, is continually exposed to contaminants throughout their entire life cycle because most meiofauna taxa have direct benthic development and a relatively sessile life style. In contrast, most macrofauna have planktonic larval stages, so only adult forms are exposed to sediment contaminants. 4) Meiofauna also have short life cycles, on the order of weeks to months, which would allow detection of toxic effects that affect only part of the life cycle. 5) Meiofauna are more abundant than macrofauna at the same site, often by at least an order of magnitude. The objective of the present study was to reassess storm water outfalls in Corpus Christi Bay using meiofauna community characteristics. The meiofaunal samples were collected at the same stations and times as samples for the macrofaunal SQT study (Carr et al. 2000). The objective of the current study was to determine if Harpacticoida and Nematoda abundance and species diversity, and Nematoda feeding groups were also inversely correlated with contaminants, and if there are differences between macrofaunal and meiofaunal community response patterns. Corpus Christi Bay is a large, open bay system, averaging only 2.3 meters in depth (Armstrong 1987), therefore wave driven re-suspension could be an important physical disturbance. A re-suspension index was estimated to characterize this disturbance at the sites during the sampling period. The SQT data from Carr et al. (2000), and new meiofaunal and Burgess et al.: Meiofaunal Assessment of Outfalls 159 Fig. 1. Sampling stations within Corpus Christi Bay, Texas, USA. Hatching indicates wetlands. physical data were analyzed with univariate and multivariate techniques to perform the reassessment and compare meiofauna response to previously described macrofauna response. Methods Corpus Christi Bay is located in the semi-arid climatic zone of Texas, U.S.A. (Fig. 1). The Nueces River drains into Nueces Bay, which is connected to Corpus Christi Bay, which is connected to the sea via Aransas Pass. The largest city bordering the Corpus Christi Bay is Corpus Christi, with a 2000 population of about 277,500 people, and is located on the south and west sides of the bay. The Port of Corpus Christi is the seventh largest port in the U.S.A. Thirty-six sites were sampled (Fig. 1, Carr et al. 2000). Twenty-eight sites were selected with suspected point or non-point source pollution based on a review of biotic and chemical studies done in Nueces and Corpus Christi Bays Meiofauna Marina, Vol. 14 (White et al. 1983; O’Connor & Ehler 1991; Barrera et al. 1995; Ward & Armstong 1996). Fifteen sites were near storm water outfalls (and named with a prefix S), 13 other sites were included because they were near point sources of anthropogenic disturbance, such as, thermal effluents, heavy industrial sites, produced waters, wastewater effluents, spoil islands, and dredged channels, these sites had no prefix. Eight reference sites (with a prefix R) were chosen because they had been used as historical reference sites (Montagna & Kalke 1992; Martin & Montagna 1995), or they were in areas with no obvious point or non-point sources of contaminants. Four sites; R6, R7, 13, and S15, were not located in the Corpus Christi Bay system, but just to the south in Laguna Madre. Detailed site descriptions and sampling methods can be found in Carr et al. (1998). A more concise description of the sampling methods can be found in Carr et al. (2000). The macrofaunal benthic index of biotic integrity (BIBI) is also provided in Carr et al. (2000). The average hourly 160 wind direction from true north and average wind speed from November 17-28 was obtained from NOAA’s National Data Buoy Data System (NOAA 1999). Water depth over submerged bars and fetch distance was estimated from Corpus Christi Bay NOAA bathymetric chart #11309. Only methods not described in these publications are described below. During sampling, meiofauna samples were collected with 1.9 cm internal diameter butylate core tubes, sampling an area of 2.84 cm2. Three cores were taken from each site. The top 2 cm of each core was extruded, placed into a 50 ml polypropylene centrifuge tube, and preserved with 3.7 % formalin buffered with 63 µm filtered seawater. Meiofauna were extracted from sediment using an isopycnic separation technique employing colloidal silica sol, Ludox® HS40 (Burgess 2001). Meiofauna were then recovered by decanting the sol through a 63 µm sieve. Extraction efficiencies was the same in samples with different sediment composition. The method had an average extraction efficiency of 97.4 ± 2.0 % for the total meiofaunal community (Burgess 2001). Harpacticoids and nematodes were identified to the lowest taxonomic level possible. Nematodes were transferred to glycerin using the method of Seinhorst (1959). A representative sample of about 100 nematodes was examined when over 200 nematodes were present in a sample. Species diversity (Shannon diversity index H' and Pielou eveness index J') for harpacticoids and nematodes was calculated by pooling all three replicates for each site. Nematodes were further identified into four feeding groups, based on their buccal morphology (Wieser 1953). Selective deposit feeders (1A) contain the species without or almost without a buccal cavity. Non-selective deposit feeders (1B) contain the species with a wide unarmed buccal cavity. Epigrowth feeders (2A) are species with a small armed buccal cavity. Predators (2B) have wide buccal cavities and glands opening on teeth. Although these categories are now recognized as oversimplified because nematodes have broader food preferences (Moens & Vincx 1997), the original four feeding groups are used in this study. Calculation of Re-suspension Index. Re-suspension of sediment by wind driven waves for each site was estimated from bottom current velocity predicted under the small amplitude wave theory (U.S. Corps of Engineers 1977). Two assumptions about the sediment were made to estimate the minimum velocity needed for resuspension. First, that the sediment was not compacted or armored, which is a good assumption for the top flocculent layer in an estuary. Second, the minimum velocity needed to re-suspension would not vary appreciably with sediment grain size (phi) between sites in the study, which is valid in this case because all the sediments fell within a phi range from silty clay to very fine sand. Within this phi range, sediment re-suspension velocities fall within in a relatively flat portion of Postma’s (1967) sediment transport curve. Therefore, a value of 12.2 cm · sec–1 was chosen, because this value would cause re-suspension in all sediment types from silt (+8 phi) to fine sand (+4 phi), which encompassed all the sediments encountered in the study area. The re-suspension index (R) was created as a percentage of a predicted wind driven wave height (H) divided by an estimated minimum wave height (Hmin) needed to produce a bottom velocity sufficient for re-suspension at the station depth: H R = ——— Hmin A value equal or greater than one hundred would indicate that sediment at a site was being re-suspended during the sample period. Wave height (H) and wave period (T) were estimated using Wilson’s shallow water formulas (Bretschnelder 1969). These formulas model fetch limited waves in shallow water: gF { –2 )) ) U2 · (0.30 · (1 – (1 + (0.004 · ——) U2 Height (H) = ————————————————— g gF | –5 ) ) U · (8.60 · (1 – (1 + 0.008 · ——) 2 Period (T) = —————————————U ———— g To obtain height and period from the equations, the values of gravity (g), wind speed (U), and fetch (F) must be known. Gravity (g), a constant, was expressed as 32 feet per second in these formulas. Average Wind speed (U) was expressed in international nautical miles per hour. Wind speed (U) and direction were obtained using vector averaging of automated buoy station data in Port Aransas (NBS 1996). Fetch (F) was estimated by a graphical method using NOAA map #11309 for Corpus Christi Bay (1991), and resultant wind direction to estimate the distance along the line from the site to the leeward shoreBurgess et al.: Meiofaunal Assessment of Outfalls 161 line. The minimum wave height (Hmin) needed to produce a bottom velocity high enough to re-suspend sediment was calculated using the wave period (T), the minimum bottom velocity needed for sediment re-suspension, and the relative depth (d/Lo) graphical method (Figure 4-20, U.S. Corps of Engineers 1977). Calculation of wave height at three sites (R3, 5, and S4) was complicated because of the bathymetry of the basin. These sites were in the leeward shadow of shallow sandbars, and additional calculations had to be made to allow for the decay of wave height due to friction with the shallow sand bottom. If the initial wave height (Hi) at the windward edge of the bar, as calculated with Wilson’s formula, exceeds the maximum stable wave height (Hmax), the wave will become unstable and decay will occur due to friction (U.S. Corps of Engineers 1977). An equivalent wave height (He) was calculated that estimates how waves would behave due to opposing forces of increasing fetch length across the bar and friction with the bar. After passing over the shallow bar, the waves were assumed to grow by Wilson’s equations again until reaching the study sites. A one-way analysis of variance (ANOVA) was performed to test for differences among sites for meiofaunal community abundance and diversity indices. Sites with no harpacticoids were omitted from the analysis. The abundance data were log (n+1) transformed and then standardized (Sharma 1996). The variables in the higher taxonomic level ANOVA were: total abundance, Nematoda, Harpacticoida, and “Others” which included the rarer taxa, Foraminifera, Gastrotricha, Kinorhyncha, Mollusca, Nemertea, Ostracoda, Tardigrada, and Turbellaria. The general linear model procedure (GLM) was used to test the null hypothesis that there were no significant differences among sites (SAS 1989). The distribution of the residual errors for each variable were examined to check if the assumption of normality had been violated (Winer 1971). Tukey multiple comparison tests were calculated on the means of each variable, to separate groups of sites that were statistically different from one another. Multivariate analysis was performed on the environmental data using principal component analysis (PCA), a multivariate variable reducing technique. The environmental data set included hydrological, contaminant, and geological variables. The PCA is sensitive to the number of variables of the input data set that are measuring the Meiofauna Marina, Vol. 14 same parameter (Kachigan 1986). Therefore, the environmental variables had to be reduced. The data reduction was accomplished in two steps. First, of the 11 trace metals measured, only the metals which exceeded the threshold effect level in sediment quality guidelines set out by MacDonald et al. (1996) and Long et al. (1995) were used in the analysis. Second, 134 species of organic pollutants were summed into the following five categories: national status and trends polycyclic aromatic hydrocarbons (NSTPAH’s), organochlorine insectides mirex and the camphenes (Chlordane), dichloro-diphenyl-trichloro-ethane known as DDT and its metabolites DDE and DDD (DDT), polychlorinated biphenols (PCB’s), and other chlorinated hydrocarbons (HCH’s). This assumes that within each class of compounds, a chemical species would have an additive effect on biological systems rather than a synergistic one. All measurement data was log (n+1) transformed and standardized, while percent data were arcsine transformed and standardized (James & McCulloch 1990). The analysis was performed using the SAS FACTOR procedure on the covariance matrix and the VARIMAX rotation procedure (SAS 1991). The SAS program is provided in (Long et al. 2003). The PCA station scores were used to correlate the environmental setting with the biological variables with Pearson product-moment correlation coefficients (r). Community structure of macrofauna species was analyzed by multivariate methods. Ordination of samples was performed using the non-metric multidimensional scaling (MDS) procedure described by Clarke & Warwick (2001) and implemented in Primer software (Clarke & Gorley 2001). The software creates a Bray-Curtis similarity matrix among all samples and then an MDS plot of the spatial relationship among the samples. The data set was plotted using the site name as the symbol. Community structure patterns for macrofauna, harpacticoids, and nematodes was compared using the RELATE procedure. Results Environment: Resuspension and Contaminants. The resuspension index varied over four orders of magnitude, ranging from 0.3 % to 300 % (Fig. 2). The index exceeded 100 %, indicating that the minimum wave height needed for re-suspension 162 Fig. 2. Resuspension index at each station. was exceeded at sites S5, S6 and S7, during the sampling interval, and therefore sediment at these sites was being re-suspended. A fourth site, S8, was above 95 % of the necessary wave height for re-suspension. One other site, S3, had approximately 75 % of the necessary wave height needed for sediment re-suspension. As expected, sand content was highest only at stations with high, greater than 50 %, resuspension indices (Fig. 3). The sandiest stations, and those with the highest resuspension index were typically stormwater (S) outfall stations, which all are named with the prefix S (Figs. 1-3). Adding the resuspension index to environ- Fig. 4. Principal component loads of all environmental variables. Fig. 3. Resuspension index as a function of sand content at each station. mental data previously analyzed improved the multivariate analysis considerably (Fig. 4). The first two principal components from the PCA of the chemical data set were retained, which explained 64 % of the variance of the original data. The first axis, ChemPC1, which represented 47 % of the variance in the original data set, indicated that trace metals strongly covaried with granulometry. The second axis ChemPC2, represented 17 % of the variance, and had high positive loadings of cyclic organic pollutants. Separation of sites by the factor scores of ChemPC1 and ChemPC2 indicated that most of the storm water outfall sites had low loadings of metals and granulometry, but a gradient from low to high cyclic organic loadings. All reference sites and most of the other sites of concern had very low loadings of cyclic organic pollutants. The two sites that did not fit into either trend had extreme values of dissolved oxygen; site 9 was supersaturated, and site S15 was anoxic. Meiofauna. Meiofaunal abundance ranged from 12,062 individuals 10 cm–2 at site 2 to 188 individuals 10 cm–2 at site S15. The average abundance for the meiofaunal community for all sites was 2099 individuals 10 cm–2 in the top 2 cm of sediment. Nematodes, at 77 %, dominated the community and averaged 1625 individuals 10 cm–2. Harpacticoid copepods comprised 6 % of the community and averaged 115 individuals 10 cm–2. The remaining 17 % of the community was composed of eight other taxa (Foraminifera, Gastrotricha, Kinorhyncha, Mollusca, Ostracoda, Nemertea, Tardigrada, Turbellaria) and averaged 359 individuals 10 cm–2. Burgess et al.: Meiofaunal Assessment of Outfalls 163 Table 1. Nematoda found during the study. Taxon, feeding group (FG), and average abundance (number/ 10 cm2) over all stations and samples. Taxon FG Abundance CHROMADORIDA Filipjev 1929 Chromadoridae Filipjev 1917 Chromadora sp. Chromadorita pharetra Ott 1972 Euchromadora sp. Neochromadora sp. Hypodontolaimus sp. Spilophorella 2A 2A 2A 2A 2A 2A 2.22 10.58 26.91 2.26 145.17 1.59 0.06 Ethmolaimidae Filipjev & Stekhoven 1941 Gomphionema sp. 2A 0.60 Selachinematidae Cobb 1915 Halichoanolaimus sp. Richtersia sp. Synonchiell sp. 2B 2A 2B 9.90 0.59 2.39 Cyatholaimidae Filipjev 1918 Pomponema sp. Paracanthonchus sp. Cyatholaimus sp. 2A 2A 2A 28.74 2.04 18.43 Desmodoridae Filipjev 1922 Eubostrichus sp. Metachromadora sp. Spirinia sp. Stilbonema sp. 1A 2A 2A 1A 1.03 150.60 4.29 2.48 Desmoscolecidae Shipley 1896 Desmoscolex sp. 0.22 Microlaimidae Micoletzky 1922 Microlaimus sp. 2A 40.51 Monoposthiidae Filipjev 1934 Monoposthia sp. 2A 19.14 Leptolaimidae Orley 1880 Camacolaimu sp. Dagda sp. Leptolaimus sp. 1A 1A 1A 0.12 0.29 7.50 Tarvaiidae Lorenzen 1981 Tarvaia sp. Ceramonematidae Cobb 1933 Ceramonema sp. Pselionema sp. Pterygonema sp. 0.15 1A 1A 1A 2.46 0.84 1.10 MONHYSTERIDA Filipjev 1929 Taxon FG Abundance Siphonolaimidae Filipjev 1918 Siphonolaimus sp. 1A 14.94 Linhomoeidae Filipjev 1922 Terschellingia longicaudata De Man 1907 Eumorpholaimus sp. Metalinhomoeus sp. Linhomoeus sp. 1A 1B 1B 1B 66.79 1.45 2.00 82.22 Axonolaimidae Filipjev 1918 Ascolaimus sp. Axonolaimus sp. Odontophora sp. Pseudolella sp. 1B 1B 2B 1B 1.00 42.26 51.13 0.09 Diplopeltidae Filipjev 1918 Areolaimus sp. Campylaimus sp. 1A 1A 1.14 0.29 Comesomatidae Filipjev 1918 Sabatieria pulchra (Schneider 1906) Paracomesoma sp. Mesonchium sp. Dorylaimopsis metatypicus Chitwood 1936 1B 1B 2B 2B 60.86 15.78 3.41 30.45 Enoplidae Dujardin 1845 Enoplus sp. 1A 0.06 Thoracosomopsidae Filipjev 1927 Enoplolaimus sp. Epacanthion sp. Trileptium sp. 2B 2B 2B 7.52 0.52 0.15 Anoplostomatidae Gerlach & Riemann 1974 Anoplostoma sp. 1B Chaetonema sp. 1B 2.62 16.99 Anticomidae Filipjev 1918 Anticoma columba Wieser 1953 1A 18.42 Ironidae de Man 1876 Dolicholaimus sp. Syringolaimus sp. 2B 2B 0.09 4.80 Leptosomatidae Filipjev 1916 Leptosomatum sp. 1A 0.22 Oxystominidae Chitwood 1935 Halailaimus sp. Oxystomina sp. 1A 1A 4.12 14.37 Oncholaimidae Filipjev 1916 Oncholaimoides striatus Chitwood 1937 Viscosia sp. Oncholaimus sp. 2B 2B 2B 19.03 35.79 17.93 Enchelidiidae Filipjev 1918 Eurystomina sp. ENOPLIA Pearse 1942 Xyalidae Chitwood 1951 4.29 Amphimonhystera sp. 1B 0.60 Paramonhystera canicula Wieser & Hopper 1967 1B 4.27 Daptonema sp. 1B 350.48 Diplolaimella sp. 1B 0.39 Gonionchus sp. 1B 6.83 Rhynchonema sp. 1B 0.34 Steineria sp. 1B 14.83 Theristus sp. 1B 52.86 Trichoheristus sp. 1B 2.72 Xyala sp. 1B 1.25 2B 2.52 Tripyloididae Filipjev 1918 Bathylaimus sp. Tripyloides sp. 1B 1B 1.19 2.23 Rhabdodemaniidae Filipjev 1934 Rhabdodemania sp. 2B 0.23 Sphaerolaimidae Filipjev 1918 Dolicholaimus sp. Sphaerolaimus sp. Trefusiidae Gerlach 1966 Trefusia sp. Tobrilus hopei Loof & Riemann 1976 1A 1A 13.29 0.44 Meiofauna Marina, Vol. 14 2A 2B 9.45 3.89 164 Fig. 5. Multidimensional scaling plot based on similarity of nematode species at all stations (MDS, 40 % similarity circled). Fig. 6. Multidimensional scaling plot based on similarity of nematode feeding groups at all stations (MDS, 80 % similarity circled). Fig. 7. Multidimensional scaling plot based on similarity of harpacticoid species at all stations (MDS, 20 % similarity circled). Fig. 8. Multidimensional scaling plot based on similarity of macrofauna species at all stations (MDS, 40 % similarity circled). Nematoda. A total 75 genera of nematodes were identified (Table 1) from 30 families. Some chromadorid and xyalid juveniles could only be identified to the family level. The dominant species were Daptonema 350 individuals 10 cm–2, Metachromadora 150.60 individuals 10 cm–2, Neochromadora 145.17 individuals 10 cm–2, Linhomoeus 82.22 individuals 10 cm–2, individuals 10 cm–2. There were five groups of stations where there was 40 % similarity of species (Fig. 5). Most outfall stations grouped together. The relative distribution of the four feeding groups was significantly different at the study sites (Fig. 6). A multivariate analysis of the feeding groups at the sites showed a significant inverse relationship between the epigrowth feeders and the non-selective deposit feeders (ANOSIM, p < 0.0001). The non-selective deposit feeders, IA, were dominated by Terschellingia longicau- data and prevalent at stations 6, R7 and 13. The selective deposit feeders, 1B, were dominated by Daptonema sp. and comesomatids and prevalent at most of the stations. The deposit feeders were well represented at stations S1 and S15 where no macrofauna were present. The epigrowth feeders, 2A, were dominant at stations 2 and S7, the two sites that also had the lowest macrofauna species diversity. Harpacticoida. The average harpacticoid species abundance ranged from 7.994 individuals per 10 cm–2 for the cletodid Enhydrosoma aff. lacunae, which was the overall dominant harpacticoid species in the bay, to 0.033 individuals per 10 cm–2 for rare species that were found only once in the study (Table 2). The five most dominant species in the study were Enhydrosoma aff. lacunae 7.99 individuals 10 cm–2, Enhydrosoma aff. herrerai Burgess et al.: Meiofaunal Assessment of Outfalls 165 5.59 individuals 10 cm–2, Halectinosoma sp. B 4.90 individuals 10 cm–2, Ectinosoma sp. A 4.71 individuals 10 cm–2, and Enhydrosoma aff. hopkinsi 4.24 individuals 10 cm–2. There was very little similarity among stations in the harpacticoid species distributions. There would be 17 station groups if we used the same 40 % similarity criteria used for nematodes. When limited to 20 % similarity, harpacticoid species were found to distribute among seven groups (Fig. 7). Most of the outfall stations grouped together. Comparison of Meiofaunal and Macrofauna Species. In the original paper (Carr et al. 2000), macrofauna species were analyzed by principal components analysis. Here we present a reanalysis of the species using MDS (Fig. 7). Using the 40 % similarity level, as with nematodes, there are five station groups and three stations that are unique. Again, the outfall stations appear to group together. Communities of all organisms (nematodes, harpacticoids, and macrofauna) basically had the same station grouping patterns (RELATE, Fig. 8). Table 2. Harpacticoid copepods found in the study. Abundance (n 10 cm–2). Taxon Abundance Longipediidae (Sars 1903) Longipedia americana (Wells 1980) 0.164 Canuellidae (Lang 1944) Coullana canadensis (Willey 1923) Coullana sp. A 0.790 0.691 Ectinosomatidae (Sars 1903) Arenosetella aff. germanica Ectinosoma sp. A Pseudobradya sp. A Pseudobradya sp. B Halectinosoma sp. A Halectinosoma sp. B Halectinosoma sp. C Halectinosoma sp. D Halectinosoma spp.(unidentified) Sigmatidium sp. A Ectinosomatidae sp. A Ectinosomatidae sp. B Ectinosomatidae sp. C Ectinosomatidae sp. D Ectinosomatidae (unidentified) 0.099 0.066 0.033 0.263 0.592 4.902 0.033 0.033 0.197 0.164 4.705 0.033 0.164 0.296 0.757 Tachidiidae (Sars 1909) Microarthridion sp. A 0.033 Harpacticidae (Sars 1904) Harpacticus chelifer (Müller 1776) Harpacticus aff. littoralis Zausodes arenicolus (Wilson 1932) Zausodes areolatus (Geddes 1968) 0.033 0.033 0.362 0.164 Peltidiidae (Sars 1904) Alteutha sp. A 0.066 Tegastidae (Sars 1904) Parategastes sp. A 0.033 Thalestridae (Sars 1905) Diarthrodes sp. A Dactylopusia sp. A 0.066 0.033 Diosaccidae (Sars 1906) Stenhelia (Delavalia) sp. A Stenhelia (Delavalia) sp. B Stenhelia (unidentified) Pseudostenhelia aff. wellsi 2.665 0.757 1.053 0.066 Meiofauna Marina, Vol. 14 Taxon Amphiascus aff. parvus Amphiascoides sp. A Amphiascoides sp. B Amphiascoides sp. C Robertgurneya hopkinsi (Lang 1965) Robertsonia aff. salsa Robertsonia sp. A Paramphiascella sp. A Haloschizopera sp. A Diosaccidae (unidentified) Abundance 0.033 0.329 0.066 0.033 0.263 0.296 0.033 0.033 0.099 1.086 Metidae (Sars 1910) Metidae (unidentified) 0.099 Tetragonicipitidae (Lang 1944) Odaginiceps sp. A 0.066 Canthocamptidae (Sars 1906) Cletocamptus aff. helobius Cletocamptus sp. A Cletocamptus sp. B Heteropsyllus sp. A Mesochra sp. A Canthocamptidae (unidentified) 2.895 0.559 0.033 0.033 0.033 0.329 Cletodidae (Scott 1905) Cletodes tuberculatus (Fiers 1991) Cletodes sp. A Enhydrosoma aff. lacunae Enhydrosoma aff. herrerai Enhydrosoma aff. hopkinsi Enhydrosoma stylicaudatum (Willey 1935) Enhydrosoma sp. A Enhydrosoma sp. B Enhydrosoma sp. C Enhydrosoma (unidentified) Cletodidae (unidentified) 0.559 0.921 7.994 5.593 4.244 0.033 0.066 0.230 0.033 1.842 3.619 Laophontidae (Scott 1905) Quinquelaophonte capillata (Wilson 1932) Laophonte sp. A Paralaophonte brevirostris (Claus 1863) Asellopsis sp. A 0.099 0.066 0.033 0.066 Thompsonulidae (Scott 1905) Thompsonula curticauda (Wilson 1932) 0.428 166 Discussion The objective of this study was to assess the impact of storm water outfalls, as well as several other point sources of pollution, on the meiobenthic community. The storm water outfalls provide a point discharge of non-point source pollutants, and the change from fresh water to oceanic salinity has resulted in increased levels of metals and organic pollutants in the sediments at several sites. However, bulk sediment chemical loads do not always predict biological availability due to sediment binding (Libes 1992). Biological communities have long been used in ecological monitoring by interpreting univariate metrics, such as species diversity and abundance with trends predicted by conceptual ecological models (Reynoldson & Rodriguez 1999). Meiofauna have been widely used to determine the effects of anthropogenic disturbance in the environment and have been shown to be sensitive to many classes of pollutants (Coull & Chandler 1992). Because of their benthic lifestyle, high abundances, short generation times, and direct benthic development, meiofauna are ideal for detecting localized pollution effects. However, since they integrate chemical and physical disturbances over time, determining if the meiofaunal community was being affected by natural or anthropogenic stressors can be difficult to resolve (Warwick 1993). The presence of nematodes at all sites, including the highly toxic sites S1 and S15 where macrobenthos were absent, indicates that they are resilient to contaminants. The composition of the trophic groups was not correlated to a single variable of toxicity assessment (Warwick & Clarke 1998). Because of the lack of information on ecological and environmental factors that could affect distribution of nematode species, we can only make broad generalized observations here. The distribution of the nematode species assemblages (Fig. 5) was different from the distribution of the nematode feeding groups (Fig. 6). This may be attributed to the heterogenous habitat and the effect of sediment type, salinity and individual species tolerance for the contaminants. The only site that was clearly distinguished from the others was R1, near the Nueces River delta, where nematode density was low and the composition of the predator/omnivore species, Sphaerolaimus sp. was high. Site 2 was the only site that was clearly differentiated in the nematode, copepod and macrofauna composition. The nematode diversity at this site was very low and dominated by a chromadorid. The cooling water discharge site in Nueces Bay had low contaminants, but exhibited high sea urchin and mysid toxicity, and the highest temperature of all sampling sites. Comparison of Environment with Communities. Community patterns and responses were related to the chemical environmental background at each station by correlating principal component (PC) scores with community characteristics (Table 3). The first PC axis (PC1) represents a gradient of sediments contaminated with heavy metals and containing high clay content to relatively clean sediments with high sand content (Fig. 4). The second PC axis (PC2) represents a contrast between high organic pollutants and low organics. The PC2 axis was a composite of the cyclic organic pollutants: organochlorinated insecticides, clorinated aromatics and polycyclic aromatic hydrocarbons. All of these pollutants strongly sorb to sediment particles (Kennish 1998), and their chemical similarities may account for the covariation. The covariation of metals and clay is probably due to both direct ionic absorption of metal ions by clay particles, and the flocculation of metal containing organic ligands which requires a relatively low energy environment (Libes 1992). Because trace metal pollutants covary with granulometry, these variables are confounded and it is not possible to separate effects due to grain size or trace metals. The toxicity data from the original study and the macrofauna benthic index of biotic integrity (BIBI) were also compared to the new PC scores with the resuspension index. Survivability in toxicity tests (i.e., urchin fertilization, urchin embryo development tests, and mysid growth) significantly decreased with increasing metals and clay content (PC1), but organics (PC2) had no effect on toxicity. The urchin embryo development and urchin fertilization tests, were pore water tests, which eliminate granulometry entirely as a factor leaving only dissolved trace metals as relevant factors on PC1. Urchins are known to be very sensitive to dissolved metals (Carr et al. 1996). These results imply that trace metals are the important variable in these tests, not granulometry. The abundance and diversity of harpacticoid Burgess et al.: Meiofaunal Assessment of Outfalls 167 copepods would be expected to decline more rapidly with increasing trace metal concentrations than the less sensitive nematodes (Coull & Chandler 1992). However, in this study harpacticoid abundance and diversity, increased with increasing trace metal and clay concentrations (Table 3). The community structure patterns were driven by high abundances of cletodids, which are morphologically adapted to an epibenthic life style, and therefore more likely to be found in low energy environments with clay/silt dominated sediments (Coull 1977). Sites estimated to have strong sediment resuspension (i.e., an index value >100, Fig. 2) had no harpacticoid copepod community regardless of the values of PC1 or PC2. Therefore, sediment granulometry plays a confounding role in determining pollution effects of trace metals. The significant negative correlations of trace metals and granulometry with nematode abundance, rare taxa abundance, and total abundance are consistent with a pollution effect under the succession theory (Rhoads et al. 1978), if trace metal concentration and not granulometry are driving the trends (as stated above). Nematodes in laboratory experiments are sensitive to metals in ranges found at some of the sites (Coull & Chandler 1992). The agreement of higher level taxa responses in the field with in vitro toxicological tests also suggests that trace metals are the causative factors affecting these three community metrics, not granulometry. Nematode abundance and the nematode/ copepod ratio decreased significantly with increasing metals. Nematode diversity did not correlate to either metals or organics. As mentioned above, the pollution effect on harpacticoid abundances was confounded by effects of Fig. 9. Relatedness of the multidimensional scaling plots for nematode, harpacticoid, and macrofauna species (Figures 5, 7, and 8). granulometry. Thus, the nematode/harpacticoid ratio could be invalid as a pollution detection metric. Also, the nematode/harpacticoid ratio was deemed unreliable for habitats other than sandy high energy sediments, where interstitial forms dominate (Raffaelli 1987). In the present study, not all sites were high energy (Fig. 2), and few truly interstitial harpacticoids were found. Therefore the validity of the ratio is suspect. Cyclic organic pollutants had significant negative correlations with harpacticoid abundance, harpacticoid species diversity measures, and the original macrofauna BIBI (Table 3). There was no significant effect of the cyclic organic pollutants in the toxicological data, suggesting that the cyclic organics may be having a chronic effect on the benthos, or only affecting a critical stage of the life cycle of these organisms. Very little work has been done with the effect of sediment bound pesticides and organic pollutants on meiofaunal communities (Coull & Chandler 1992). However, because of the intimate association of meiofauna and macrofauna with sediments, it is expected that critical developmental stages could be affected. Table 3. Matching environmental variables with community metrics. Pearson correlation coefficients and significance level, but no correlation is given if not significant. Metric *Toxicity *Macrofauna BIBI Nematode abundance Harpacticoid abundance Nematode/Copepod Ratio Harpacticoids H' Nematodes H' * Data from Carr et al. 2000 Meiofauna Marina, Vol. 14 PC1 (Metals/Clay) PC2 (Organics) –0.44 (p=0.008) (p=0.482) –0.41 (p=0.014) 0.35 (p=0.038) –0.37 (p=0.037) 0.36 (p=0.029) (p=0.993) (p=0.507) –0.37 (p=0.025) (p=0.709) –0.38 (p=0.021) (p=0.750) –0.37 (p=0.025) (p=0.952) 168 Conclusions In the original study (Carr et al. 2000), toxicity was correlated to contaminants and inversely to the macrofauna index of biotic integrity. However, there was no correlation between sediment contaminants and macrofauna community responses. Four of five most degraded sites were outfalls (S1, S2, S9, S15, 2) In the current study, the four most contaminated outfall sites (S1, S2, S9, S15) had reduced macrofaunal and meiofaunal ecological integrity as indicated by reduced levels of abundance and similar community composition patterns. The finding that macrofauna was affected by sediment quality is opposite from the earlier (Carr et al. 2000) study because of the improved multivariate analysis performed on the sediment quality data presented here. The improved anlaysis also allowed distinguishing between heavy metal and organic contaminant effects. Metals negatively affected nematode abundance, but organics negatively affected macrofauna biotic integrity and harpacticoids abundance and diversity. Resuspension was a confounding factor with organic pollutants at five relatively clean outfall sites, where harpacticoids were absent and macrofauna were negatively affected. Nematode feeding group composition was similar at all sites. Overall, meiofauna results compared well to macrofauna results, but increased our understanding of contaminant effects caused by outfalls. 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McGraw-Hill Book Company, New York. 170 Burgess et al.: Meiofaunal Assessment of Outfalls MEIOFAUNA MARINA Biodiversity, morphology and ecology of small benthic organisms INSTRUCTIONS TO CONTRIBUTORS Meiofauna Marina continues the journal Microfauna Marina. It invites papers on all aspects of permanent and temporary marine meiofauna, especialls those dealing with their taxonomy, biogeography, ecology, morphology and ultrastructure. Manuscripts on the evolution of marine meiofauna are also welcome. Publication of larger reviews or special volumes are possible, but need to be requested for. Meiofauna Marina will be published once a year. All contributions undergo a thorough process of peer-review. Manuscript format: Manuscripts must be in English with metric units throughout. All parts of the manuscript must be typed, double-spaced, with margins at least 2.5 cm. Number all pages. Submit original plus 2 copies to facilitate reviewing and editing. Online-submission of manuscripts via the Meiofauna Marina homepage (www.meiofauna-marina.com) will be possible soon, but one of the editors must additionally be notified by e-mail or mail. Page 1: Cover page including title of the paper; name(s) and address(es) of author(s); number of figures and tables. Suggest up to 5 keywords not in the title, and a short running title of no more than 50 characters. Indicate to which author correspondence and proofs should be sent; include e-mail, phone and fax numbers for this person. Page 2: Concise abstract summarizing the main findings, conclusions, and their significance. Page 3 and following pages: The Introduction, usually a brief account of background and goals, must be titled. Subsequent sections also bear titles, usually Material and Methods, Results, Discussion, Acknowledgements and References, but these may vary to suit the content. Subsections may be subtitled (don’t number subtitles). Figure legends, tables, and footnotes (in that order) should follow on extra pages following the References. Citations and references: Complete data for all published works and theses cited, and only those cited, must be listed in References in alphabetical order; include papers accepted for publication (Cramer, in press), but not those merely submitted or in preparation. In the text, cite works in chronological order: (Smith & Ruppert 1988; Cook et al. 1992; Ax 1998a,b). Cite unpublished data and manuscripts from one of the autors (Smith, unpublished) or other individuals (E. E. Ruppert, pers. comm.) with no entry in References. Consult BIOSIS for journal-title abbreviations. Examples of reference style: Pesch, G. G., C. Müller & C. E. Pesch (1988). Chromosomes of the marine worm Nephtys incisa (Annelida: Polychaeta). Ophelia 28: 157-167. Fish, A. B. & C. D. Cook (1992). Mussels and other edible Bivalves. Roe Publ., New York. Smith, X. Y. (1993). Hydroid development. In: Development of Marine Invertebrates, vol. 2, Jones, M. N. (ed.), pp. 123199. Doe Press, New York. Illustrations and data: In designing tables, figures, and multiple-figure plates, keep in mind the final page size and proportions: 140 mm wide and maximally 200 mm high. Figures may occupy one column (68 mm) or two columns (140 mm). Details of all figures (graphs, line drawings, halftones) must be large enough to remain clear after reduction; type should be 1.5 mm high after reduction. Please submit original line drawings; they will be reduced to final size by the publisher. Copies (submitted as hard copies or online) must be sufficiently good for reviewers to judge their quality. Include a scale bar and its value in each figure (value may be stated in the legend); do not use magnification. Authors are encouraged to submit extra, unlabelled photographs or drawings (black and white or colour) to be considered for the back cover of the journal. For final publication, photographic prints must be mounted, leaving no space between multiple prints on a plate. Protect each figure with a tissue cover sheet, and keep all materials within the size of the manuscript sheets, for safe and easy mailing. Digital images and charts must be of high quality and professionally built. For more information visit “www.pfeil-verlag. de/div/eimag.php”. Even if photographs or line drawings are processed with graphics programs, original slides, negatives or drawings must always be submitted. Scientific names: For all species studied, the complete scientific name with taxonomic author and date (e.g., Hesionides arenaria Friedrich, 1937) should be given either at the first mention in the text of the paper or in the Material and Methods, but not in the title or abstract. Thereafter, use the full binomial (Hesionides arenaria) at the first mention in each section of the paper, and then abbreviate (H. arenaria, not Hesionides unless referring to the genus). Names for higher taxa should refer to monophyletic units, not to paraphyla (use, e.g., Macrostomida or Dinophilidae but not designations such as Turbellaria or Archiannelida). International nomenclature conventions must be observed, especially the International Code of Zoological Nomenclature (IRZN). The Latin name of any taxon is treated as a singular noun, not a plural or an adjective. Strictly, a taxon should not be confused with its members (the taxon Cnidaria does not bear nematocysts, but cnidarians do). Avoid terms of Linnean classification above the genus level. Submitting a diskette: To facilitate speed and accuracy of publication, authors should supply a diskette after acceptance of the manuscript. Authors should retain a computer file that corresponds exactly to the hard-copy manuscript. Use a single standard font, a single space between sentences, and a single tab to indent each paragraph; avoid justifying, hyphenating, etc. Specialized word-processing commands (except boldface, italics, superscript, subscript) will have to be stripped from the final file. Use italics for species and genus names only. Complete instructions for diskettes will be sent with notification of acceptance. Proofs, reprints, charges: 20 reprints are free of charge. Color plates must be paid by the authors. Additional reprints can be ordered by the authors. MEIOFAUNA MARINA Biodiversity, morphology and ecology of small benthic organisms Volume 14 ISSN 1611-7557